This invention relates to surgical staples of the type which are bent around an anvil by a pusher in a surgical stapler.
Surgical staplers for applying staples to close incisions or wounds in body tissue are shown, for example, in Green et al. U.S. Pat. No. 3,643,851, Smith, U.S. Pat. No. 3,650,453, Green U.S. Pat. No. 3,837,555 and Noiles et al. U.S. patent application Ser. No. 181,092, filed Aug. 25, 1980, now abandoned, entitled "Improved Surgical Staples." Such staples have become widely known and used in recent years and typically are preformed and have a broad-based square-cornered "U" shape.
In the staplers, the staple is urged toward an anvil by a bifurcated pusher with a generally "U"-shaped recess between its twin heads. The base of the "U"-shaped recess in the pusher is broader than the anvil but not as broad as the base of the "U"-shaped staple. When the staple reaches the anvil, the heads of the bifurcated pusher cause the staple to bend around the anvil into a closed, square-cornered "C" or rectangular shape.
During bending, the ends of the staple enter the tissue, below the anvil, and draw the tissue on opposite sides of the wound or incision together. After bending is complete, the pusher is retracted from the staple and the anvil is slid out from within the staple. The staple remains in the tissue to hold it together during healing.
However, a significant problem is that the staples frequently are not bent symmetrically about the anvil because the staple becomes off-center during forming. As a result, the sharp ends of the staples are misaligned within the tissue being stapled, one end being too deeply embedded in the tissue and the other end not deeply enough.